In Command Under Supervision is recognized as PIC time by both customers and licensing authority, sometimes to a maximum amount or percentage. Think about all those cadet programs where you go from an R22 license directly to an S92 copilot. 5 years later how do you get the PIC time to qualify for an ATPL or meet oil company minimums for captain? (P)ICUS is the only option. No value for single-pilot bush work, but driving the bus on the railroad track to an offshore platform and back on the same base for 20 years it can be made to work.
Most companies have formal guidelines on how to "qualify" a particular flight for PICUS (commander qualification, briefing, copilot experience level, CP letter on file etc.). However when applying outside your previous company I doubt if any "credible" number you put down would or could ever be challenged.